The gigantic starship Ark was launched on a voyage of ten-thousand years from an Earth on the brink of collapse. Its mission was to carry a portion of the human race to a new home circling ather star - but, centuries after its departure, the descendants of the original crew longer remember that they are on a city-sized spaceship, and kw thing of the Ark's mission, r of the starry universe outside. The Prophetsy, a theocracy based on slavery and terror, has ruled over most of the Ark for longer than anyone w living can remember, and it has just succeeded in conquering the few remaining free regions of the ship. Yet there are chinks in the molithic tyranny...